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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.onlab.onos.openflow.controller.impl;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import org.projectfloodlight.openflow.protocol.OFFactories;
import org.projectfloodlight.openflow.protocol.OFMessage;
import org.projectfloodlight.openflow.protocol.OFMessageReader;
/**
* Decode an openflow message from a Channel, for use in a netty pipeline.
*/
public class OFMessageDecoder extends FrameDecoder {
@Override
protected Object decode(ChannelHandlerContext ctx, Channel channel,
ChannelBuffer buffer) throws Exception {
if (!channel.isConnected()) {
// In testing, I see decode being called AFTER decode last.
// This check avoids that from reading corrupted frames
return null;
}
// Note that a single call to decode results in reading a single
// OFMessage from the channel buffer, which is passed on to, and processed
// by, the controller (in OFChannelHandler).
// This is different from earlier behavior (with the original openflowj),
// where we parsed all the messages in the buffer, before passing on
// a list of the parsed messages to the controller.
// The performance *may or may not* not be as good as before.
OFMessageReader<OFMessage> reader = OFFactories.getGenericReader();
OFMessage message = reader.readFrom(buffer);
return message;
}
}